本文使用VB.Net来判断目录或文件是否存在的代码例子，用的着网友参考一下了！   
  Imports System.IO
    Public Class Form1
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        If Boo_DirExist("C:\Lob.cn\") Then
            MsgBox("存在C:\Lob.cn\目录")
        Else
            MsgBox("不存在C:\Lob.cn\目录")
        End If
        If Boo_FileExist("C:\Lob.txt") Then
            MsgBox("存在C:\Lob.txt文件")
        Else
            MsgBox("不存在C:\Lob.txt文件")
        End If
    End Sub

'判断目录是否存在的函数,传入String值,返回Boolean值

    Private Function Boo_DirExist(ByVal Str_Path As String) As Boolean
        Boo_DirExist = System.IO.Directory.Exists(Str_Path)
    End Function

'判断文件是否存在的函数, 传入String值,返回Boolean值

    Private Function Boo_FileExist(ByVal Str_File As String) As Boolean
        Boo_FileExist = System.IO.File.Exists(Str_File)
    End Function
End Class